Re: [PATCH 4/8] firmware: qcom: scm: Add support for ARM64 SoCs

Bjorn Andersson
2016-04-23T14:18:21Z

On Fri 22 Apr 21:52 PDT 2016, Andy Gross wrote:

> On Fri, Apr 22, 2016 at 04:41:05PM -0700, Bjorn Andersson wrote:
> > On Fri 22 Apr 15:17 PDT 2016, Andy Gross wrote:
[..]
> > > diff --git a/drivers/firmware/qcom_scm.c b/drivers/firmware/qcom_scm.c
> > > index 8e1eeb8..7d7b12b 100644
> > [..]
> > >
> > > +static void qcom_scm_init(void)
> > > +{
> > > + __qcom_scm_init();
> > > +}
> > > +
> > > static int qcom_scm_probe(struct platform_device *pdev)
> > > {
> > > struct qcom_scm *scm;
> > > @@ -208,6 +213,8 @@ static int qcom_scm_probe(struct platform_device *pdev)
> > > __scm = scm;
> > > __scm->dev = &pdev->dev;
> > >
> > > + qcom_scm_init();
> > > +
> >
> > Why don't you call __qcom_scm_init() directly here?
>
> Yeah that would save some stack ops.
>
> As a side note, what do you think about just making the first transaction on the
> scm-64 side do this init to figure out 32/64 calling convention?
>
> That would eliminate this mess.
>

We will have quite a bunch of entry points in this API, so it will
probably be messier to have them all call some potential-init function.

Perhaps if it's possible to push it to the __qcom_scm_call{,_atomic}.
But I'm not sure we want those to be more complicated just to save this
one call...

> > > return 0;
> > > }
> > >
> > > diff --git a/drivers/firmware/qcom_scm.h b/drivers/firmware/qcom_scm.h
> > [..]
> > > +#define QCOM_SCM_V2_EBUSY -12
> > > #define QCOM_SCM_ENOMEM -5
> > > #define QCOM_SCM_EOPNOTSUPP -4
> > > #define QCOM_SCM_EINVAL_ADDR -3
> > > @@ -56,6 +58,8 @@ static inline int qcom_scm_remap_error(int err)
> > > return -EOPNOTSUPP;
> > > case QCOM_SCM_ENOMEM:
> > > return -ENOMEM;
> > > + case QCOM_SCM_V2_EBUSY:
> > > + return err;
> >
> > I don't think return -ENOMEM is the right thing to do here.
>
> -EBUSY?
>

That seems better.

> > > return -EINVAL;
> > > }

Regards,
Bjorn